CHAPTER 5: Olefin (Co)polymerizations Enabled by Catalyst Design Based on Sidearm Strategy

A series of group IV metal catalysts was designed by using the “Sidearm Strategy”. The sidearm group is envisioned to act as a controller of the shape and/or electronic properties of the catalytic site and so to tune the behaviours of olefin (co)polymerization. As expected, the coordination pattern of the newly-designed ligands with titanium tetrachloride leads to complexes of monoligand trichloro titanium, and this result makes the steric space of the active site for polymerization readily tunable via variation of the sidearm. In the presence of MMAO, these complexes show excellent activity to copolymerize ethylene and comonomer. 1-Alkenes, cycloolefins, ω-alkenol, ω-alkenoic acid, and ω-alkenoic ester could be incorporated into the PE backbone efficiently. In addition, both SHOP type nickel complexes and bisoxazolines were modified by the sidearm strategy. Based on this simple strategy, the activity of the resulting nickel complexes increased obviously and the newly-designed SaBOX played the key role in a highly syndiospecific (>90% rr) and controlled ATRP of methyl methacrylate (MMA), allyl methacrylate (AMA) and vinyl methacrylate (VMA) under mild polymerization conditions.